Over the past year, Ford has driven about 500 test subjects to distraction inside VIRTTEX, a vast white dome perched on spidery hydraulic legs, 11 feet off the laboratory floor in Dearborn, Mich.

Inside the 24-foot-diameter dome, subjects settle into a Ford Taurus for a convincing simulation of real-world driving--complete with G-forces, sound, motion and a wrap-around projection of the road and traffic.

Buckled inside for a brief test, I even experience a moment of motion sickness while cruising a simulated I-94 between Jackson and Marshall, Mich. With a headset strapped on, I'm asked to dial a hands-free phone while keeping pace with traffic. Cars zoom past, and a weaving driver looms in my left-side mirror.

Real test subjects spend about an hour behind the wheel as the control room crew monitors multiple views of the interior. Digital cameras and low-power lasers focus on the subject's irises, with an electronic headset helping technicians detect where eyes are focused.

It looks like the world's biggest video game. But the object is deadly serious.

The National Highway Traffic Safety Administration estimates that 25 percent of crashes are caused by some form of distraction, spokesman Tim Hurd said. Rear-end collisions alone cost the nation $30 billion a year in broken cars and broken bones, according to Ford.

Preliminary VIRTTEX results show that a ringing phone may be more distracting than talking on the phone while driving.

And teens may be at higher risk for distraction-related accidents. Younger drivers have a lot more trouble managing multiple tasks while driving than adults, despite teens' superior skills with gadgets and gizmos.

The reason? Inexperience.

"Teens have much more problem with split-attention tasks than an adult who's been driving for 30 years," said Larry Cathey, a technical specialist at Ford's Scientific Research Laboratory. Young drivers are more prone to straying from their lane when trying to do two things at once. They're not good at dividing attention between dialing a phone and driving, tending to stare at the digits instead of taking regular glances at the road.

Those conclusions might come as no surprise to any parent, but Cathey said the studies are still important. "A lot of it sounds like common sense, but you have to back that up with objective data, to settle the arguments in public and government on how to manage the workload safely," he said.

Ford plans to share its results with the government, other manufacturers and researchers. Such studies could point the way to industry and government standards for safely operating phones and other devices.

New York has banned the use of hands-on cell phones while driving, and 42 states, including Illinois, are considering similar legislation. General Motors Corp. is researching the issue, and supports the use of hands-free devices in automobiles.

When it comes to studying distraction, fake driving beats the real thing, Hurd said. "It's impossible to do this kind of testing on the road, because you can't endanger the driver or other people," he said.

Ford will use VIRTTEX to study how drivers can safely interact with new technology, such as cameras that analyze traffic around the car and alert drivers to potential hazards.

Ford technical specialist Ron Miller said it's important to build cars that give drivers needed information but don't look like the cockpit of a fighter jet. "We have to understand the psychology of driving like never before," he said.